Receiver technology for radio astronomy and deep space communications

This thesis presents the design and development of a complete receiver system for a conversion project, which replaces the commercial receiver of a telecommunication antenna with a cryogenically cooled radio astronomy receiver. Part of the project is to explore the synergy between radio astronomy and deep-space communications, which share many technical requirements, but also have technical conflicts. Therefore, this thesis attempts to solve some of these technological issues and provides a design for a receiver system, where radio astronomy and communication applications can successfully share the same hardware and infrastructure. The receiver system employs a FPGA-based digital signal processing backend, which enables the instrument to be used in three different operational modes, single-dish observation, interferometer observation, and deep-space communication. The architecture of the receiver system includes a novel technical solution to stabilise gain drift when used in single-dish observation mode. Two stabilisation methods are discussed in detail, and their performance is verified by measurements. The white-noise stabilisation approach uses a modulated reference noise signal and the continuous-wave stabilisation approach uses a narrowband reference signal to track the change in am- plification. Both stabilisation methods showed excellent performance and are implemented to stabilise the gain drift of the receiver system. A number of analogue signal components were specially designed for the receiver system in order to meet the requirements of the conversion project. One of these components is the compact quad-ridged orthomode transducer, which provides the transmission between the feed horn and the coaxial cables. Its design uses a novel approach to reduce significantly the transition length, while retaining a wide operational bandwidth. Finally we present the design of the complete receiver system, which includes the development work and verification of the components that were built for this project.